XV Workshop on Philosophical Logic

August 5–7, 2026

IIF - SADAF - CONICET

Buenos Aires, Argentina

Thomas Macaulay Ferguson (Rensselaer Polytechnic Institute, USA)

Ulf Hlobil (Concordia Univesrity, Canada)

Franci Mangravitti (ETH Zurich, Switzerland)

Alba Massolo (National University of Córdoba, Argentina)

Cláudia Nalon (Department of Computer Science, University of Brasília, Brazil)

Elena Wüllhorst (King's College London, UK)

Wednesday 05/08 (GMT-3)

14:00 – 15:00 TBA

15:10 – 16:10 TBA

16:10 – 16:50 coffee break

16:50 – 17:50 TBA

18:00 – 19:00 TBA

Thursday 06/08 (GMT-3)

15:00 – 16:00 TBA

16:10 – 17:10 TBA

17:10 – 17:50 coffee break

17:50 – 18:50 TBA

19:00 – 20:00 TBA

20:00 and on Workshop Dinner

Friday 07/08 (GMT-3)

14:00 – 15:00 Edson Bezerra (IIF-SADAF-CONICET)

15:10 – 16:10 TBA

16:10 – 16:50 coffee break

16:50 – 17:50 TBA

18:00 – 19:00 TBA

Edson Bezerra: "Modal Metainferential Hierarchies"

TBA

Bruno Da Ré: TBA

TBA

Thomas Macaulay Ferguson: "n-Sided Consequence, n-Lateralism, ans Suszko's Thesis"

TBA

Ulf Hlobil: "Inference and Object"

I first present an extension of Implication-Space Semantics (as developed in Hlobil and Brandom, 2025) that includes first order quantification. I then raise the question whether this theory is consistent with the idea that propositions are primary, relative to their non-propositional parts. I present an account of names and predicates in terms of assertoric sentences and their inferential roles. The account can be translated into an account of objects and properties in terms of worldly propositions (which are things that are made true or false by states) and the alethic modal relations among them. The account exploits symmetries of modal structures. In slogan form: properties are what is common among symmetric points in modal space; objects are what differs among symmetric points in modal space.

Franci Mangravitti: "Formalism freeness and nonclassical logics"

Building on remarks by Gödel on computability, Juliette Kennedy presents the notion of formalism freeness as ‘the idea that certain canonical concepts and constructions are stable across a variety of conceptually distinct formalisations, so seemingly insensitive to perturbations of logic and syntax’. This can manifest as logic-independence, i.e. ‘invariance under substitution of one of a class of logics, considered on a case by case basis’ (as in the notion of set constructibility, where infinitely many logics between first- and second-order end up converging on one of two notions) and the giving of a purely mathematical definition of some prima facie logical notion (as in Birkhoff’s characterization of axiomatizable classes of algebras as being closed under certain algebraic operations). Crucially, `formalism freeness is not an all or nothing affair, but a matter of degree'.

While Kennedy focuses on classical mathematics and extended classical logics, I argue that formalism freeness can be a fruitful guiding principle for nonclassical logics, especially in contexts where the philosophical reasons to insist on one logic over another are slim. Looking at a variety of case studies from the inconsistent mathematics literature, I will argue that a search for formalism freeness is already implicit in much work being done, and point to several results which are best understood under this lens. I will also discuss why one might want, and how it might look, to put formalism freeness first. My conclusion is that keeping an active eye for formalism freeness - both its failures and its successes - can have significant benefits.

Cláudia Nalon: "Efficient Theorem-proving for Modal Logics"

Modal logics have been extensively studied, as they can express non-trivial problems ranging from domains in Mathematics and Philosophy to the representation of computational systems. The implementation of reasoning engines for those logics is, therefore, highly desirable. However, the satisfiability problem for even the most basic of the multimodal logics, the modal logic Kn, is not tractable: local and global reasoning in the multiagent set are PSPACE-complete and EXPTime-complete, respectively. We are, thus, interested in calculi that can be effectively employed for reasoning within those logics in an efficient way. In this talk, we will discuss two different resolution-based calculi for the multimodal Kn with particular focus on the characteristics that have an impact on automatic theorem-proving. We will report on experimental results and the influence of proof strategies and processing techniques for both calculi, and how different techniques impact the efficiency of theorem-proving in practice.

Alba Massolo: "Rethinking Evidence: Logical Intuitions in Methodological Anti-exceptionalism"

Anti-exceptionalism about logic (AEL) challenges the traditional view of logic as an a priori, foundational, and exceptional discipline, instead arguing for its continuity with the empirical sciences. A key distinction within this debate, advanced by Martin and Hjortland (2022, 2025), separates methodological AEL the claim that logical theories are evaluated like scientific ones—from evidential AEL, which maintains that the evidence for logical theories does not differ from that of the empirical sciences. Although these two dimensions are often treated as independent—permitting the use of scientific methodologies while retaining exceptional sources of evidence—this presentation challenges that assumption.

Focusing on logical intuitions, I argue that both predictivism and abductivism—the two main variants of methodological AEL—implicitly rely on theory-independent evidence to avoid justificatory circularity. Yet recent empirical research in cognitive science suggests that logical intuitions are neither a priori nor theory-independent; rather, they function as “educated guesses” shaped by formal education and expert practice. Consequently, logical intuitions cannot serve as the theory-neutral data that predictivism and abductivism require. Instead, I contend that logical intuitions, as experientially shaped and revisable, align far more naturally with a coherentist methodology such as reflective equilibrium. This approach explicitly accommodates bidirectional adjustment between inferential practices and logical principles. Thus, this presentation not only highlights a challenge for predictivists and abductivists but also outlines a constructive alternative for anti-exceptionalism.

Mauro E. Santelli: TBA

TBA

Damián Szmuc: "Regular logical matrices as monoidal matrices"

This presentation aims to show how regular logical matrices can be seen as a special instance of the monoidal matrices introduced by Cintula, Gil-Férez, Moraschini, and Paoli in 2019. For this purpose, we consider a regular logical matrix $R$, later discussing its monoidal matrix representation $M^{R}$, and finally introducing its induced hypermatrix $H^{M^{R}}$. We will ultimately be able to show that the Tarskian consequence relation $\vDash_{\rm R}$ over the Set-Formula framework is equivalent to the multiset deductive relation $\vDash_{\rm H^{M^{R}}}$ over the Multiset-Formula framework. To conclude, we ponder the prospects of generalizing these techniques to present monoidal and hypermatrix counterparts for p-, q-, and b-matrices. Among other things, this would suggest the possibility of producing, e.g. a monoidal p-matrix and a corresponding hyper p-matrix for the sequent calculus G3c, when rules are formulated over multisets.

Paula Teijeiro: "Local bayesianism for local validity"

Metainferences are a higher level relation of forcing between inferences instead of formulas. How to properly determine which of them are valid remains an open debate. One of the most widespread definitions in the run, what is called `local validity’, amounts to satisfaction preservation from premises to conclusion. Those who argue against this characterization claim that it lacks a proper interpretation, and therefore, that it is just a technical tool, neither principled nor philosophically interesting. In this work, we propose a way to understand local validity by means of an epistemic interpretation: we will take locally valid metainferences to be those which preserve certain kind of evidence.

Elena Wüllhorst: TBA

TBA

Camillo Fiore (UBA/IIF-SADAF-CONICET)

Mariela Rubin (UBA/IIF-SADAF-CONICET)

Joaquín S. Toranzo Calderón (UBA/UTN/IIF-SADAF-CONICET)

Victor Valderrama (IIF-SADAF-CONICET)

We are thankful for the support provided by CONICET